3D Micro‐Network Li/Al ₄ Li ₉ Composite Anodes Constructed by One‐Step Melt‐Spinning for High Energy Density Lithium Metal Batteries

ABSTRACT

Lithium‐metal anodes are hindered by inhomogeneous lithium plating/stripping, interfacial side reactions, and volume expansion. The lithium alloy anodes are considered an effective strategy to resolve these problems, but they suffer from structural degradation during cycling. Herein, a 3D micro‐network Li/Al ₄ Li ₉ composite anode is fabricated via one‐step melt‐spinning. The microstructure evolution of the alloy ribbons is studied systematically by tuning the cooling conditions. Ultimately, a uniform Li/Al ₄ Li ₉ composite anode with a 3D micro‐network is achieved at a copper roller speed of 2200 rpm. The intrinsic Li/Al ₄ Li ₉ composite anode structure provides synergistic functions: first, the interconnected micro‐network provides continuous electron/ion transport pathways and abundant reaction interfaces, which lowers the nucleation barrier and uniform lithium plating/stripping; second, the Li/Al ₄ Li ₉ composite anode with Al ₄ Li ₉ skeleton shows high Young's modulus, which buffers volume expansion and uniform stress distribution. In situ optical microscopy and post‐cycling SEM images confirm the Li/Al ₄ Li ₉ composite anode exhibits excellent mitigate structural degradation ability. The Li/Al ₄ Li ₉ ||Li/Al ₄ Li ₉ cells in ether‐based electrolyte demonstrate stable cycling for 1600 h at 1 mA cm ^{− 2} , 1 mAh cm ^{− 2} , and Li/Al ₄ Li ₉ ||LiFePO ₄ cells in carbonate‐based electrolyte retain 81.7% capacity after 204 cycles at 0.5 C. Impressively, the Li/Al ₄ Li ₉ composite anode is a promising anode for high‐energy‐density lithium metal batteries.